"OS X 10.9, which is internally codenamed 'Cabernet', will focus on various 'power-user' enhancements and take core features from iOS, according to our sources. Unlike operating system updates such as OS X Leopard and OS X Lion, OS X 10.9 will likely not be an overhauled approach to how the operating system feels and functions." Features for power users and features from iOS? Seems like an oxymoron. Still, if they manage to finally fix the Finder and Spaces, I'll be happy.

If you mean HFS, it was designed in 1985 for the Macintosh - a single threaded OS at the time. The fact we are still using HFS is slightly perplexing, but it's not the exact same version as the 1985 vintage. HFS+ changed things quite a lot, and since then Apple have added case sensitivity and journalling (HFSX and HFSJ.) Yes, I think we'd all like something a little less tied to another age, but those that cry over HFS+ usually do so because of the bad memories of Classic Mac, rather than the fact that it is "fairly" stable and "pretty" reliable now.